The U.S. Food and Drug Administration has expanded its approval of Dysport (abobotulinumtoxinA) as a treatment for spasticity in adults from not just the upper limbs but to the lower limbs as well, according to its maker, Ipsen Biopharmaceuticals.
Spasticity can affect those with amyotrophic lateral sclerosis (ALS), multiple sclerosis, cerebral palsy, stroke, traumatic brain injury and spinal cord injury.
The FDA approved Dysport in July 2015 as a treatment for upper-limb spasticity in adults. In July 2016 it approved it for treating lower-limb spasticity in children aged 2 and older. That made it the first botulinum toxin approved for that situation. Now the FDA has expanded the lower-limb approval to adults.
“Dysport is currently the only botulinum toxin approved by the FDA for the treatment of spasticity in adults in upper and lower limbs and also for the treatment of lower limb spasticity in children ages 2 and older,” Cynthia Schwalm, president of Ipsen’s North America commercial operations, said in a press release.
Spasticity, or shaking, occurs when there is an abnormal increase in muscle tone or stiffness. It often interferes with movement.
Lower-limb spasticity commonly involves the gastrocnemius and soleus muscle complex in the calf. We use calf muscles when we raise our heel from the ground to walk.
There are several degrees of spasticity, ranging from mild to painful, uncontrollable spasms.
Dysport is an injectable form of botulinum toxin type A. The therapy, made from the bacteria that causes botulism, blocks nerve activity in muscles, causing a temporary reduction in muscle activity.
Results of a Phase 3 clinical trial supported Ipsen’s application for Dysport’s approval. The randomized, double-blind, placebo-controlled study (NCT01313312) covered people with lower limb spasticity resulting from stroke or traumatic brain injury.
The study enrolled 381 adults randomized to receive one of two Dysport doses or a placebo at least six months after a stroke or brain injury.
The ankle muscle tone of those who received Dysport improved, the study showed. That was particularly true of the higher-dose group.
Most patients’ response lasted 12 to 16 weeks, but some responded up to 20 weeks.
The most common adverse effects during the trial included muscle weakness, pain in extremities, and falls.
Like all botulinum-toxin products, Dysport can cause symptoms similar to botulism that start in the injected area and spread to other parts of the body.
The symptoms include swallowing and breathing difficulties that can be life-threatening. That’s why Ipsen warns people not to use Dysport if they have had a serious reaction to any botulinum toxin-related product, if they are allergic to cow’s milk, or if they have an infection at the proposed injection site.